<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>div盒子标签</title>
	<style>
		.box{
			width:200px;
			height: 200px;
			background: red;
		}
		.son{
			width: 100px;
			height: 100px;
			background: blue;
		}
	</style>
</head>
<body>
	<div class="box">
		<div class="son">
			son
		</div>
	</div>
	<div class="box">
		box2
	</div>
</body>
</html>